PMHS-reduced fabrication of hollow Ag–SiO₂ composite spheres with developed porosity

Abstract

A one-pot method was introduced to fabricate Ag–SiO₂ hollow composite spheres with developed porosity by employing monodisperse carboxylic-capped polystyrene (PS–COOH) spheres as a hard template. During the synthetic process, Ag⁺ ions were immediately anchored on the surface of the PS–COOH spheres via electrostatic interaction and readily reduced by employing polymethylhydrosiloxane (PMHS) as a reducing agent. At the same time, silica oligomers derived from the hydrolysis of PMHS and TEOS were slowly deposited on the PS–COOH spheres to form solid silica shells. Subsequent decomposition of the PS–COOH spheres in air induced the formation of Ag–SiO₂ hollow spheres. The as-prepared products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N₂ absorption–desorption study. The results show that the well-designed composite spheres featured thin and spherical silica shell (~10 nm), large surface area (>240 m² g⁻¹) and mesopore (6.0–9.0 nm). In addition, the Ag–SiO₂ hollow composite spheres exhibited high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).

Graphical Abstract

A one-pot method was reported to prepare Ag–SiO₂ hollow spheres with well-developed porosity, which exhibited high catalytic performance and durable activity for the reaction of 4-NP to 4-AP.